The fate and transport of sediment plumes in the ocean, such as those resulting from the disposal of deep-sea mining residuals, are affected by ambient crossflow. We present laboratory measurements of the depth at which a particle plume is trapped by ambient stratification for various crossflow and particle settling velocities. Results suggest that the trap depth declines exponentially with crossflow velocity but is relatively insensitive to settling velocity in the range studied. An empirical correlation based on the laboratory data is validated by a larger scale field experiment involving simulated disposal of deep-sea mining wastes.
We conduct pore-scale simulations of two-phase flow using the 2D Rothman–Keller colour gradient lattice Boltzmann method to study the effect of wettability on saturation at breakthrough (sweep) when the injected fluid first passes through the right boundary of the model. We performed a suite of 189 simulations in which a “red” fluid is injected at the left side of a 2D porous model that is initially saturated with a “blue” fluid spanning viscosity ratios $$M = \nu _\mathrm{r}/\nu _\mathrm{b} \in [0.001,100]$$ M=νr/νb∈[0.001,100] and wetting angles $$\theta _\mathrm{w} \in [ 0^\circ ,180^\circ ]$$ θw∈[0∘,180∘] . As expected, at low-viscosity ratios $$M=\nu _\mathrm{r}/\nu _\mathrm{b} \ll 1$$ M=νr/νb≪1 we observe viscous fingering in which narrow tendrils of the red fluid span the model, and for high-viscosity ratios $$M \gg 1$$ M≫1 , we observe stable displacement. The viscous finger morphology is affected by the wetting angle with a tendency for more rounded fingers when the injected fluid is wetting. However, rather than the expected result of increased saturation with increasing wettability, we observe a complex saturation landscape at breakthrough as a function of viscosity ratio and wetting angle that contains hills and valleys with specific wetting angles at given viscosity ratios that maximize sweep. This unexpected result that sweep does not necessarily increase with wettability has major implications to enhanced oil recovery and suggests that the dynamics of multiphase flow in porous media has a complex relationship with the geometry of the medium and the hydrodynamical parameters.
Given their environmental abundances, it has been long hypothesized that geochemical interactions between reactive forms of manganese and nitrogen may play important roles in the cycling of these elements. Indeed, recent studies have begun shedding light on the possible role of soluble, ligand-bound Mn(III) in promoting abiotic transformations under environmentally relevant conditions. Here, using the kinetic data of Karolewski et al. (Geochim Cosmochim Acta 293:365–378, 2021), we provide the chemical mechanism for the abiotic oxidation of nitrite (NO2−) by Mn(III)-pyrophosphate, MnIIIPP, to form nitrate (NO3−). Nitrous acid (HNO2), not NO2−, is the reductant in the reaction, based on thermodynamic and kinetic considerations. As soluble Mn(III) complexes react in a one-electron transfer reaction, two one-electron transfer steps must occur. In step one, HNO2 is first oxidized to nitrogen dioxide, ·NO2, a free radical via a hydrogen atom transfer (HAT) reaction. We show that this inner sphere reaction process is the rate-limiting step in the reaction sequence. In step two, ·NO2 reacts with a second MnIIIPP complex to form the nitronium ion (NO2+), which is isoelectronic with CO2. Unlike the poor electron-accepting capability of CO2, NO2+ is an excellent electron acceptor for both OH− and H2O, so NO2+ reacts quickly with water to form the end-product NO3− (step 3 in the reaction sequence). Thus, water provides the O atom in this nitrification reaction in accordance with the O-isotope data. This work provides mechanistic perspective on a potentially important interaction between Mn and nitrogen species, thereby offering a framework in which to interpret kinetic and isotopic data and to further investigate the relevance of this reaction under environmental conditions.
My aim was to write a short, clear, useful, and interesting guide to the ?ndings in renal biopsy specimens. Particular parts of this aim were to show how a diagnosis can be reached,and what informatio
The design of most cities prioritizes the use of motorized vehicles, having a negative effect on urban health. A major concern in the European Union (EU) is air pollution, especially nitrogen dioxide (NO2), which causes many inhabitants health problems and decreases the quality of life. A non-expensive way to reduce pollutants is implementing road restriction policies, as the creation of low emission zones. In this work, we analyze the case of Madrid Central, a low emission zone deployed in Madrid, Spain. We evaluate if it was effective to reduce air pollutants and if there were a side effect, as pollution displacement, during its application. Drawing on open data, we analyze air quality at different points of the city, before and during the application of this measure. Taking into account the EU directives in terms of what healthy air means, we consider three metrics: (a) the trend of NO2 concentration in the air in both periods, (b) the difference between the NO2 concentration during both periods, and (c) the percentage of time in which the population is exposed to air with NO2 concentration under a specific threshold (healthy air as defined by the EU). According to the results, Madrid Central significantly reduces the NO2 concentration in the air and does not produce pollution displacement. Thus, the population breathes healthy air during more time, and there is a positive effect on the whole city.
In the medical diagnosis, urinanalysis has a significant role in the recognition of many infections, diabetes and kidney diseases. In this article, photonic crystal (PhC) micro ring resonator (MRR) is proposed for different hematological or renal disorders where the concentrations of different components of urine can be detected using refractive index (RI) variation of urine. The proposed sensor works on the principle of resonance wavelength shift due to analytes having different RI and is simulated using FDTD simulation. High sensitivity is achieved with the reported structure as 720 nm/RIU for various glucose concentrations, 830 nm/RIU for various albumin concentrations and 701 nm/RIU for different urea concentration in the urine and the structure would be beneficial for various sensing purpose.
In this study, new and existing methods of estimating stroke volume, cardiac output and total peripheral resistance from analysis of the arterial blood pressure waveform were tested over a wide range of conditions. These pulse contour analysis methods (PCMs) were applied to data obtained in six swine during infusion of volume, phenylephrine, dobutamine, isoproterenol, esmolol and nitroglycerine as well as during progressive hemorrhage. Performance of PCMs was compared using true end-ejection pressures as well as estimated end-ejection pressures. There was considerable overlap in the accuracies of the PCMs when using true end-ejection measures. However, for perhaps the most clinically relevant condition, where radial artery pressure is the input, only Wesseling's Corrected Impedance method and the Kouchoukos Correction method achieved statistically superior results. We introduced a method of estimating end-ejection by determining when the systolic pressure dropped to a value equal to the sum of the end-diastolic pressure plus a fraction of the pulse pressure. The most accurate estimation of end-ejection was obtained when that fraction was set to 60% for the central arterial pressure and to 50% for the femoral and radial arterial pressures. When the estimated end-ejection measures were used for the PCMs that depend on end-ejection measures and when radial artery pressure was used as the input, only Wesseling's Corrected Impedance method and the modified Herd's method achieved statistically superior results. This study provides a systematic comparison of multiple PCMs' ability to estimate stroke volume, cardiac output, and total peripheral resistance and introduces a new method of estimating end-systole.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) does not describe the typical symptoms noted by researchers of pediatric bipolar disorder under bipolar I or II because there is a great deal of controversy over whether bipolar disorder exists in children. Researchers who have gathered data on children who experience irritability, mood swings, elevated moods, inattention, hyperactivity, defiance, compulsive behaviors, sadness, and sleep problems have called the condition either pediatric bipolar disorder (PBD; for children 3–12) or early-onset bipolar disorder (EOBD; for children 13–18). Students with PBD or EOBD have little control over their mood swings and irritability, calling for a combination of pharmacological and environmental interventions along with close monitoring of any side effects and evaluation of the effectiveness of interventions. Bipolar disorder in children is considered a progressive condition that manifests differently as the child ages, moving from more irritability, restlessness, and rapid mood swings to less frequent mood swings but longer depressive moods.
Coral reefs construct the most bustling metropolis in the oceans. Known as the “rainforests of the sea,” coral reefs form some of the most diverse ecosystems. They provide many complicated marine habitats to support a wide range of other living beings. There are diverse coral reef organisms, such as sponge, sea anemone, coral algae, etc. besides corals. A coral reef is one of the most vital ecosystems on Earth and plays an irreplaceable role in maintaining the biodiversity and ecological balance of the oceans. B. Liao (*) Shenzhen Institute of Guangdong Ocean University, Shenzhen, People’s Republic of China B. Xiao Shenzhen Institute of Guangdong Ocean University, Shenzhen, People’s Republic of China Guangdong Ocean University, Zhanjiang, People’s Republic of China Z. Li Marine Biotechnology Laboratory, State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
We explore why and how corporations seek to build community resilience as a strategic response to grand challenges. Based on a comparative case study analysis of four corporations strategically building community resilience in five place-based communities in South Africa, as well as three counterfactual cases, we develop a process model of corporate practices and contingent factors that explain why and how some corporations commit to community resilience building and whether they try to do so directly or indirectly. We thus help explain corporations' strategic contributions to community resilience, and we emphasise the role of place-specific resources, social-ecological system viability, and limited statehood in motivating such organisational responses to grand challenges.
The epistemology of self-locating belief concerns itself with how rational agents ought to respond to certain kinds of indexical information. I argue that those who endorse the thesis of Time-Slice Rationality ought to endorse a particular view about the epistemology of self-locating belief, according to which ‘essentially indexical’ information is never evidentially relevant to non-indexical matters. I close by offering some independent motivations for endorsing Time-Slice Rationality in the context of the epistemology of self-locating belief.
